Means for ascertaining the integrity of two-line conductors



May 16, 1933. OHAGAN 1,909,711

MEANS FOR ASCERTAINING THE INTEGRITY OF TWO-LINE CONDUCTORS Filed Feb. 11, 1932 INVENT OR Bernard F. OHagan BY dam-W HIS ATTORNEY Patented May 16, 1933 BERNARD E. OHAGAN, F SWISSVALE, PENNSYLVANIA, AS$IGNOR TO THE UNION M SVIZTCH & SIGNAL JQMIPAIIY, 9E S'iItTSSVALE, PENNSYLVANIA, A CORPORATION 01* PEH'NSYLVANIA MEANS FOR ASGERTAINING- THE INTEGRITY OF TW'O-LIIIE CONDUCTOBS Application filed February 11, 1932. Serial No. 592,251.

The present invention relates to means or ascertaining the integrity of two line conductors, such as the running rails of a track section, and has for its main object and feature the detection of a break in one of the running rails of a track section Whereby such condition adversely affects traffic controlling means, such as a signal or a brake-setting means, on the train.

In the accompanying drawing the in vcntion is shown in several concrete and preferred forms, in which:

Fig. 1 is a diagrammatic representation oi so much of a track and train equipment, embodying one form of the invention, as

necessary to understand the invention;

Fig. 2 is a diagrammatic view similar to Fig. 1, but showing a modified form of the invention; and

3 is a diagrammatic view similar to Fig. l, but showing a second mocified form of the invention.

in the exemplification of the invention shown in Fig. 1, the reference characters 1 and 2 indicate conductors, here the running rails of a track section, on which rails voltage is impressed in any of the ways known in the art. T1 is a train-carried device consisting here of a plate 3, a grid i and a filament Device T1 is responsive to the influence of current iio in rail 1 by.

reason of receiver or coil R1 and transformer 6, the secondary of which latter is 1ncluded in the input or grid-filament circuit of T1, and the primary oi wlnchtransformer is included with coil R1 in a'tuned circuit. included in the plate-filament or output circuit of T1 is the primary of a transformer 7, the secondary or" said transformer 7 being in series with a rectifier 8. Bridged around said rectifier is a large capacity C1. T2 is a second train-carried device consisting here of plate 9, grid 10 and filament 11, and this device is responsive to the influence of current flow in the other rail 2 by reason of receiver or coil R2 and transformer 12, the secondary of which latter is included in the input circuit of T2 and the primary of which transformer is included with coil 32 in a, tuned circuit. MB is a trafic controlling device of suitable character, here shown as a relay, to control one or more signals or a brake valve or both.

Relay MB is included in circuit with the Grid 4 oi device T1 has a negative bias of such character that the voltage induced by rail 1 will render such grid alternately positive and negative to thereby cause current to flow in the plate filament circuit of T1. If current is absent in rail 1, the plate-filament c rrent of T1 will be zero. Grid 10 of device T2 is made negative to such an extent (indicated here by 32 volts) that normal current flowing in rail 2 will not effectively influence said grid 10 and consequently current in rail 2 alone will not be sufiicient to control relay MR. It will be seen, however, that the output circuit of rectifier 8 is connected by wire 8a to grid 10 so that, when device T1 is energized by current from its associated rail 1, the output of rectifier 8 will counteract the negative bias of grid 10 to such an extent that current in rail 2, associated with device T2, will effectively infiuence grid 10. This action will in turn modulate the current in the plate-filament or output circuit of T2 thereby controlling amplifier or rectifier 1 1- and relay MB. Therefore devices T1 and T2 must both be energized i'rom rails 1 and 2 respectively to cause relay ME to respond, for if rail 1 be broken and current is not received by T1, grid 10 will retain its abnormal negative bias, and conversely if rail 2 be broken grid 10 will receive steady direct current owing to filtering action of C1 across rectifier 8, and steady direct current applied to grid 10 will not cause current to fiow in the output circuit of device T2.

In the form of the invention shown in. Fig. 2 a screen 19 is added to the grid of device or tube T2 and the screen grid characteristics of the tube are utilized in the following manner: In this form or the inven tion, the grids of T 1 and T 2 are both biased negatively to approximately the same extent, that is devices T1 and T2 will be en ergized by the influence of the normal current flow in rails 1 and 2 respectively, and when no current tlows in l and 2, the output circuits or. T1 and T2 will be zero. Screen 190i grid 10, however, acts to block current flow in the plate-filament circuit even when current is present in rail 2. But said screen 19 is connected by wire 8?) to the positive terminal of rectifier S, the negative terminal of the latter being connected to the filament circuit by wire 20, with the result that the output of rectifier 8 places positive potential on screen 19 thereby reducing the inipedance oi the plate-filament circuit of T2 to the point where current in rail 2 will cause current to flow in said plate-filament circuit of T2. Capacity C1 shunts rectifier 8 and will lilter the direct current, so that, in case current is only pr .nt in rail 1, there will be no danger of 1110C. dating the screen grid of T2 by alternating current ripples from the rectifier, which ripples might have the effect of causing current flow in the output circuit of T2. Thus, in order to control relay MR, it is necessary to receive energy both from rails 1 and 2, as the presence of current in one of said rails alone will not cause current flow in the output circuit of T2.

In the form of the invention shown in Fig. 8, indirectly heated cathodes 21, 22 and 23 associated with T1, T2 and 14, and resistors R3 and R4 are interposed in the connections leading to cathodes 21 and 22. In this case, as in the form shown in Fig. 1, the grid of T1 has a normal grid bias to prevent i'low of current in its plate circuit except when normal current is flowing in the rail under R1, and the grid of T2 has a very large bias so that no normal current flowing under R2 will cause current to flow in the plate circuit of T2. When normal current fiows under R1, the plate current of T1 produces a voltage drop across resistor R?) which makes the grid ct T2 more positive and allows plate current to flow in T2 it there is normal current in the rail under H2. If an excessive current should flow in the rail under R2, then any tendency to set up a plate current in T2 is counteracted by a voltage drop across R4 which by making cathode 22 positive increases the bias of the grid of T2, thereby limiting the plate current of T2. The values of resistors and R4 are so selected that when R1 and Q2 both energized the grid of T2 becomes positive to a greater degree than does the cathode of T2, thereby efiecting a decrease in the negative bias of the grid of T2.

I claim:

1. A train control system including: a track section composed 01 charged running rails, a train-carried device, having an input and an output circuit, to respond to the influence of current flow in one of said rails, a second train-carried device, having an input and an output circuit, to respond to the influence of current flow in the other of said rails, rectifying means associated With the output circuit of the first device to control the input circuit of the second device, and trafiic controlling means controlled by the output circuit of the second device.

2. A train control system including: track section composed of charged running rails, a trai -carried device, having an input and. an output circuit, to respond to the influence of current flow in one of said rails, a second train-carried device, having an input and an output circuit, to respond to the influence of current flow in the other of said rails, rectifying means associated with the output circuit of the first device to control the second device, and tratlic controlling means controlled by the output circuit of the second device.

3. A train control system including: a track section composed of charged running rails, a train-carried device to respond to the influence of current flow in one of said rails, a second train-carried device, having a plu rality of elements including a grid, to respond to the influence of current flow in the other of said rails, means to negatively bias said grid to the extent of preventing normal current flow in said other rail from effectively influencing said second device, and means to counteract the negative bias of the grid when the first device is energized by its rail to thereby permit the current in the other rail to effectively influence the grid of the second device.

4. A train control system including: a track section composed of charged running rails, a train-carried device to respond to the influence of current flow in one of said rails, a second train-carried device, having a plurality of elements including a grid, to respond to the influence of current flow in the other of said rails, means to negatively bias said grid to the extent of preventing normal current flow in said other rail from eilectively influencing said second device, and rectitying means associated with the first device to counteract the negative bias of the grid when the first device is energized by its rail to thereby permit the current in the other rail to effectively influence the grid oi the second device.

Signed at Swissvale, in the county or Alle heny, and Commonwealth of Pennsylvania, this 9th day of Februai", 1932.

BERNARD E. DHAGAN. 

